Roll position control



June 1962 T. w. LASIEWICZ ETAL 3, 9, 3

ROLL POSITION CONTROL Filed April 15, 1960 '2 Sheets-Sheet 1 I 26T38- J61 n I ELECTRIC CONTROL CIRCUIT 18 Ln/mam.

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United States Patent 3,039,513 ROLL PUSITION CONTROL Thaddeus W. Lasiewicz, Mentor, and Robert J. Shafer, Poland, Ohio, assignors to GPE Controls, Inc., Chicago, 11]., a corporation of Illinois Filed Apr. 13, 1960, Ser. No. 22,017 Claims. (Cl. 153-87) This invention relates to the metal working art, and more particularly to a roll position control for use in flexing a moving strip of metal.

In the fabrication of certain metals, such as in strip rolling of sheet steel, it is the practice to use one or more vertically adjustable rolls to flex the steel as it passes thereunder, in order to produce various results, such as for example, scale breaking or crust removal, reduction of any tendency for the strip to cross break or flute, and for work hardening the strip steel. For the sake of convenience, the invention will be described as used in scale breaking operations. However, it is to be understood that the arrangement illustrated and described may be used to produce the other results enumerated by way of example. A common method for regulating the position of the adjustable roll involved the use of manual position setting means which generally included the use of a screw adjustment at each end of the roll. Such methods for adjusting a roll are unsatisfactory because they are too time consuming, and are not flexible, or rapid enough to provide satisfactory results under variable conditions.

The roll position control of the present invention provides a rapid and CfilCleIll. means for regulating the position of a roller in sheet flexing operations. In addition, the roll position control of the present invention features a bias setter which allows selective positioning of one end of a roll, whereby the lateral travel of the sheet material under process may be adjusted.

Briefly, the invention comprises the use of power cylinders arranged at each end of a roll, which cylinders may be used for movement of either both, or only one end of the roll. The position of the roll is maintained by means of a power system including a pair of jet pipe regulators having electro-magnetic means adapted to control movement of a jet pipe regulator, which system automatically maintains the desired position of the roll. Feed-back means directly connected to each end of a roll yoke, are adapted to transmit a position feedback signal to the jet pipe electromagnetic positioning means. Two control knobs are provided, the first of which may be set to establish desired overall positioning of the roll, and the second of which may be set to tilt or bias the roll by moving one end up or down relative to the other end, for maintaining correct lateral position of the web as it passes beneath the roll. The knobs may be mounted upon a control panel at some distance from the location of the roll and the regulating means therefor, thus providing an effective and convenient arrangement for flexing sheet steel in strip mill operations. The accuracy and speed associated with the position control means of the invention, contributes immeasurably to the production of a superior product.

The main object of this invention is to provide a roll position control which may be used for conveniently regulating the flexing of sheet metal in a rolling operation.

A more specific object of the invention is to provide a roll position control adapted for automatically adjusting the position of the roll.

Still another object of the invention is to provide a roll position control which may be used to automatically regulate lateral movement of a sheet material as it passes beneath the roll.

3,039,513 Patented June 19, 1962 Still another object of this invention is to provide a roll position control means which may be located at some distance from the roll, thus providing remote position control of the roll.

These and further objects and features of the invention will be set forth in the following description and accompanying drawings wherein:

FIG. 1 is a schematic illustration showing the arrangement of a scale breaker roll in a rolling mill;

FIG. 2 is a diagrammatic illustration showing a scale breaker position control arrangement representative of an embodiment of the invention; and

FIG. 3 is a schematic wiring diagram of the electrical circuitry used in the arrangement shown in FIG. 2.

Referring now to the drawings, and more particularly to FIG. 2, numeral 10 identifies a scale breaker roll which is journalled at both ends and supported by a frame means 12. Affixed at each extremity of the frame 12, are pressure responsive motor means in the form of pistons 14, 14 slidably arranged in cylinders 16, 16. Means are provided to supply pressurized hydraulic medium to the cylinders 16, 16' to cause movement of the frame means 12 whereby the scale breaker roll 10 may be positioned as required for removing scale from the sheet material being processed. As is best seen in FIG. 1, the roll 10 is arranged for movement between spaced rollers 18, 18'. The position of the scale breaker roll 10 relative to the fixed rollers 13, 18 will determine the amount or degree of flexure applied to a moving sheet of steel 20, as is required for breaking the scale therefrom.

Liquid medium under pressure is directed to the cylinders 16, 16' by means of spool valves 22, 22' which serve to provide control of large amounts of fluid. A conduit or hose such as 24 or 24' connects each spool valve with the upper end of each cylinder, while a conduit or hose such as 26 or 26' connects each spool valve with a lower end of its associated cylinder. Liquid under pressure is fed from a high pressure liquid source (not shown) by pipe 28 to each spool valve 22. It will be seen that when a spool valve is in its upper position liquid flow will occur to the upper end of an associated cylind er via pipe 24, to cause downward movement of the piston assembly 14, while movement of the spool valve toward its lower position will result in liquid flow to the lower end of a cylinder via pipe 26 or 26' to cause upward movement of the piston assembly. Return flow pipes 30, 30' are associated with each spool valve assembly wherebyliquid release is provided from each cylinder, from that end toward which a piston assembly 14, 14 is moving.

Movement of each spool valve is effected by connection to a jet distributor piston 32 or 32 slidably arranged in a cylinder 34 or 34', respectively. Each piston 32 or 32 is formed to provide a pair of passageways such as 36, 38 in piston 32, one end of each passageway being arranged in spaced relation at the side of piston 32 while the opposite end of each passageway opens into an opposite end surface of piston 32. A jet pipe 40 is pivotally arranged at one end and has its opposite end in spaced relation to the side openings or orifices of passageways 36, 38. A pipe or hose means 42 is arranged to supply hydraulic fluid under pressure to each jet pipe 40 or 40' for jetting fluid from the free end thereof. It will be seen that rotary movement of jet pipe 40 toward the orifice provided by the open end of the passageway 36, will result in upward movement of the distributor piston 32, while rotary movement of the jet pipe toward the orifice formed by the open end of passageway 38, will result in downward movement of the distributor piston 32. Rotary movement of jet pipe 40 is controlled by two means, the first of which comprises an electromagnetic means having a floating coil 44 secured to the jet pipe and arranged to move Within a magnetic field provided by permanent magnet 46. The second means controlling position of the jet pipe is an adjustable spring 4-8 adapted to oppose outward movement of the coil 44 from the magnet 46 by compression, and adapted to oppose inward movement of the coil by tension. In the absence of any current through coil 44, spring 48 determines the position of jet pipe 40, and accordingly adjustment of spring 48 can be efiected to balance piston 32 at its center point with no current in coil 44. With a given polarity amplified error signal current applied to coil 44, the flux from the coil will interact with the permanent magnet flux so as to attract the coil and jet pipe 46, against the tension of spring 48. With an opposite polarity current applied to the coil, the coil and jet pipe 40 will be repelled, against the compression of spring 48. The jet supply pipe 42 is connected to the liquid supply pipe 28, while a reduction valve 50 and pressure gauge 52 are arranged in the pipe 42 for regulation of liquid flow to each jet pipe 40. The jet-pipe regulator system shown in FIG. 2 for controlling piston 14' and the right end of roll may be identical to that provided for the left end.

Electrical means for positional control of the jet pipes include a single bias control means 54, a position set control means 56, a pair of position feed-back means in the form of potentiome-ters 58, 59 each being coupled for movement by one of the piston assemblies 14 or 14, and an electrical circuit arrangement 60 adapted to receive input signals from the controls 54, 56, and potentiometers 58, 59, and to send a control signal in accordance therewith to each of the jet pipe electro-magnetic means.

For a better understanding of the control system operation, reference may be had to FIG. 3, wherein the electric circuit connections are shown. Direct voltage from a conventional D.C. power supply (now shown) is applied to conductors 101 and 102, across a series circuit including a portion of the winding of bias set potentiometer 62, the winding of position set potentiometer 66 and a portion of the Winding of bias set potentiometer 64. As indicated, the wiper arms of bias set potentiometers are mechanically positioned by manual adjustment of bias set control knob 54. The series circuit mentioned above comprises two adjacent arms of a bridge circuit. The other two arms of the bridge circuit comprise a series circuit connected between conductors 161, 102 and including the unshorted portion of calibration potentiometers 8t and 82 and the winding of position feedback potentiometer 70. The arm of potentiometer 70 is mechanically positioned in accordance with the position of the left-hand end of roll 10, by means shown in FIG. 2 as comprising a rack and pinion. The wipers of position set potentiometer 66 and position feedback potentiometer 70 comprise the output terminals of the bridge. These terminals are connected as shown to provide the input signal for a conventional D.C. amplifier 74, which amplifies the signal to provide operating current for coil 44 of regulator 70. Assume, for sake of analysis that, from a balanced condition, position set knob control 56 is rotated so as to move the arm of potentiometer 66 rightwardly as shown in FIG. 3, toward a more negative potential. The unbalance signal will be amplified immediately by amplifier 74, exciting coil 44 of jet-pipe regulator 70 so that the coil flux acts with the permanent magnet flux so as to attract jet pipe 40, thereby causing upward movement of piston 32, and application of pressure through conduit 26, thereby raising piston 14 and the left end of roll 10. Raising the left end of roll 10 operates potentiometer arm 58 so as to move it rightwardly also, in FIG. 3, thereby balancing the bridge, so that the amplifier input returns to zero, and thejet pipe 40 returns to the zero force set point established by spring 48. If position set knob 56 is rotated in the opposite direction, converse operation occurs, with an opposite polarity input being applied to amplifier 74, so that coil 44 is repelled rather than attracted, causing downward movement of piston 32, piston 14 and the left end of roll 10. It may be noted that fluctuations in power and supply voltage do not unbalance the bridge, and hence they cannot affect roll position.

As mentioned above, regulator 70' controlling the right end of roll 10 may be identical to regulator 70 and as shown in FIG. 3, regulator 76' is controlled by a similar bridge circuit, two arms of which comprise calibration or adjustment rheostat 78 and position set potentiometer 68, and the other two arms of which are formed by the winding 72 of position feedback potentiometer 59. It may be noted that no bias set control need be included in the control circuit for regulator 70'. Since position set control knob 56 is mechanically connected to adjust potentiometer 68 as well as potentiometer 66, the abovedescribed adjustments of position set knob 56 will cause simultaneous and equal adjustments of the two ends of roll 10 by the simple adjustment of a single control.

As shown in FIG. 3, bias set control knob 54 positions simultaneously the arms of identical potentiometers 62 and 64, moving them together, either both rightwardly or both leftwardly as shown in FIG. 3. It will be seen that adjustment of bias set control knob 54 in either direction operates to raise or lower equally the voltages applied at both ends of the winding of potentiometer 66, but without changing the magnitude of the voltage drop across potentiometer 66. Changing the excitation of potentiometer 66 unbalances the bridge circuit and provides an error signal input to amplifier 74, which results in movement of the left end of roll 10 in the same manner as heretofore described. Because bias set knob 54 does not control the circuit feeding amplifier 76 and regulator 70', adjustment of this control does not affect the position of the right hand end of roll 10. It may be noted that because adjustment of bias control 54 does not change the magnitude of the voltage across potentiometer '66, it does not aifect in any way the position set adjustments made by means of position set control knob 56. Similarly, it may be seen that adjustment of position set knob 56 and the arm of potentiometer 66 does not affect the bias adjustments made by means of knob 54. Such independence between the two controls is an extremely important advantage.

It will be seen that the described electrical circuitry functions to automatically provide simultaneous movement of each piston assemblage 14 in either direction as position set control knob 56 is varied. In addition the electrical circuitry, by adjustment of bias control knob 54, will provide movement of only one piston assemblage 14, resulting in movement of the left end of the scale breaker roll ltl relative to the stationary other end thereof. In such manner, not only is the desired position of the scale breaker roll 10 maintained to accomplish effective scale removal, but an easy correction may be made for any camber in the strip being run to thus keep the strip tracking in the center of the line. It is to be noted that the bias setting of a roll will be maintained even though the position control is readjusted.

From the foregoing, it will be seen that the scale breaker position control of the present invention functions to provide a fast and accurate means for removing scale from sheet material such as in strip mill operations, and greatly aids in the fabrication of an improved finished product.

The foregoing description has been given in detail without thought of limitation since the inventive principles involved are capable of assuming other forms Without departing from the spirit of the invention or the scope of the following claims.

What is claimed is:

1. Apparatus for metal-working, comprising, in combination: a roll stand through which a material may be fed, including an adjustable roll movable at both ends; motive means mechanically connected to adjust the two ends of said roll, either jointly or independently; first and second position-measuring transducers mechanically connected to be adjusted by motion of the first and second ends of said roll and operable to provide electrical signals commensurate with instantaneous positions of the ends of said roll; a first control means for efiecting simultaneous and equal adjustments of both ends of said roll; a second control means for effecting movement of one end of said roll relative to the other end of said roll; and electric circuit means responsive to said electrical signals and to said first and second control means and operative to control said motive means.

2. Apparatus according to claim 1 in which said adjustable roll is movable vertically and in which said roll stand includes two stationary further rolls spaced apart, wherein said adjustable roll is capable of being positioned partially on both sides of a plane tangent to said stationary rolls, thereby to flex material passed through said roll stand.

3. Apparatus according to claim 1 in which said motive means comprises a pair of hydraulic cylinder piston assemblies connected to position individual ends of said adjustable roll.

4. Apparatus according to claim 1 in which said first and second transducers each comprise an electrical potentiometer connected to be adjusted by movement of an individual end of said roll.

5. Apparatus according to claim 1 in which said first control means comprises a first pair of mechanicallyganged potentiometers.

6. Apparatus according to claim 1 in which said second control means comprises a pair of mechanically-ganged otentiometers.

7. Apparatus according to claim 1 in which said elec tric circuit means includes a pair of electrical signal amplifiers and a pair of electro-hydraulic power-amplifying means.

8. Apparatus according to claim 1 in which said first and second transducers comprise a first and second electrical potentiometers, in which said first controlmeans comprises third and fourth mechanicallyganged potentiometers, said first potentiometer and said third potentiometer being connected in bridge circuit relationship to provide a first error signal, said second and fourth potentiometers being connected in bridge circuit relationship to provide a second error signal, and in which said electric circuit means includes first amplifier means responsive to said first error signal and operative to control said motive means to adjust one end of said roll, and second amplifier means responsive to said second error signal and operative to control said motive means to adjust the other end of said roll.

9. Apparatus according to claim 7 in which said electro-hydraulic amplifying means comprises a jet pipe biased by a spring to a neutral point, a stationary permanent magnet, a coil mechanically connected to said jet pipe and adapted to receive signal currents thereby deflecting said jet pipe against the restraint of said spring, a pair of receiver ports and a piston adapted to receive fluid directed by said jet pipe, and a proportioning valve connected to be controlled by said piston.

10. Apparatus according to claim 8 in which said second control means comprises fifth and sixth mechanically-ganged potentiometers connected to vary the voltages at the ends of said third potentiometer with out varying the magnitude of the voltage across said third potentiometer.

References Cited in the file of this patent UNITED STATES PATENTS 2,545,921 Goodwillie Mar. 20, 1951 2,790,229 Hellstrom Apr. 30, 1957 2,857,655 Greenberger Oct. 28, 1958 2,961,901 Wheeler Nov. 29, 1960 FOREIGN PATENTS 647,606 Great Britain Dec. 20, 1950 

